2. The Objective
7/26/2012
To formulate the Pd-Sn/C binary
alloyed catalyst for EOR to
determine its activity towards
ethanol electrooxidation in alkaline
medium
2
3. Experimental, Pd-Sn/catlysts synthesis
• Pd-Sn/C catalysts were synthesised by the
modified polyol method followed by supporting
carbon black (Vulcan XC72R).
• (33.3 mg SnCl2+12 mL Ethylene Glycol (EG)+1
mL DI water) heating 80C+1 hr reac.
• 26 mg of K 2 PdCl4+3 mL of EG+ 8 mL of pre-
heated EG 130C + 0.02mmol Sn solution
• 30 min reaction + argon flow+ C black
4. Experimental- charachterization
• The high-angle annular dark field HAADF-
TEM, & electron energy loss spectroscopy
(EELS)
• XRD Bruker AXS instrument equipped with a
GADDS (GeneralArea Detector Diffraction
System) detector
• Chemical compositions;Pd-Sn:PGT Imix-PC
energy dispersive X-ray spectroscopy (EDS)
5. Electrochemical Measurements
• Using 3-electrode cell; GCE working
electrod, platinum wire counter electrode &
Hg/HgO (1 M KOH) reference electrode
• Nafion working solution:Nafion 117 ∼ 5
wt% mixed of lower aliphatic alcohols and
water
• DFT Calculations: by dual basis set, using
the Gaussian and plane waves (GPW)
method.
6. Conclusion
• C supported Pd−Sn nanoparticles via a polyol
method
• Pd−Sn/C catalysts: two times higher peak current
densities than Pd/C in CV measures
• Sn content charge transfer rate during EOR
• EOR on Pd−Sn catalysts partial oxidation of
ethanol forming acetic acid
• Future: complete:EOR DFT calculation Pd−Sn
(facile synthetic route& enhancing EOR
7. international journal of hydrogenenergy36(2011)9994-9999
Performance of an alkaline-acid
direct ethanol fuel cell
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
8. Electrochimica Acta 55 (2010) 3002–3007
Carbon supported Pd–Co–Mo alloy as an
alternative to Pt for oxygen reduction in
direct ethanol fuel cells
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
9. Journal of Power Sources 190 (2009) 241–251
Pd and Pt–Ru anode electrocatalysts supported on
multi-walled carbon nanotubes (MWCNTs) and their
use in passive and active direct alcohol fuel cells with
an anion-exchange membrane (alcohol = methanol,
ethanol, glycerol)
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
10. Experimental-Materials analysis & Catalyst
preparation
• MWCNTs: by CVD & treated with H2SO4 50%
(v:v) for 14 h & (HNO3 65%, 120◦C, 8 h)
• MWCNTs Pd & Pt-Ru: [Pt(CH3)2(COD)], [Ru
(COD)(COT)], [Pd2(dba)3]
• Pd/MWCNT: 1gm MWCNT+ 50ml THF+
sloution [Pd2(dba)3] (.25gm) in 50 ml THF
• Pt-Ru/MWCNT: 65ml toluene aerated with
argon+2gm MWCNT,1hr sonication+ 1gm [Ru
(COD)(COT)] + 0.7gm [Pt(CH3)2(COD)]
11. Experimental- Active & Passive DAFCs
Active DAFC with Au-
The home-made DAFC: to
evaluate the performance
plated current collectors
of Pd/MWCNT anodes, and Ti end plates for
passive DAFC alkaline purpose
A dense anode ink was
prepared by mixing the
powdered catalyst with a 5–
10 wt.% aqueous dispersion
of PTFE.
14. 7/26/2012
Polarization and power density curves at
different temperatures of active DAFC with
a Pd/MWCNT anode (metal loading 1 mg
cm−2 ), fuelled with an aque- ous 2 M KOH
solution of (A) methanol (10 wt.%); (B)
ethanol (10 wt.%); (C) glycerol (5 wt.%).
Inset report the temperatures of fuel (left),
cell (central), oxygen gas (right).
14
15. Conclusion
• The MWCNT-supported Pd nanoparticles are
effective catalysts for alcohol oxidation DAFC
• (MEA) containing a Pd/MWCNT anode,Fe-Co
Hypermec™ cathode &Tokuyama A-006 AEM
provided excelent results
• Ethanol: oxidized on Pd/MWCNT to acetic acid,
to acetate ion in the alkaline media.
• DMFC: Pd/MWCNT is more active than Pt-
Ru/MWCNT
16. S.Y. Shen et al. / Electrochimica Acta 55 (2010) 9179–9184
Carbon-supported bimetallic PdIr
catalysts for ethanol oxidation in
alkaline media
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
17. Literature review
• Non-noble metal catalyst is na advantage of AEM
in alkaline media EOR in DAFCs
• Ethanol as alcohol: high energy density, less
toxic, can be transported in large quantities.
• Pd has bothe higher activity for EOR and steady
state behavior in alkaline media than Pt.
• Pd: alloyed (Au, Sn, Ru, Ag, Ni, Pb or Cu)
• This work: to have PdIr/C by simultanous red.
18. Experimental- Catalyst synthesis
• All chemicals in DI water
• PdCl2, H2IrCl6, K3C6H5O7, NaBH4, KOH, HCl, &
ethanol (CH3CH2OH) were used.
• Catalysts sythesised by simultaneous reduction
method using cericate as complexing agent and
stabilizer
• Dissolution in DI water+ K3C6H5O7 + suspending
Cpowder+ filteration+drying Pd/C ci-Pd/C
catalysts
19. Experimental- Physicochemical,
electrochemical characterizations
• XRD (scan rate of 0.025◦/s)
• TEM at 200 kV
• XPS Al monochromatic X-ray at a power of 350
W
• CV, LSV and CP: conventional 3-electrode cell:
(GCE) of 0.1256 cm2-working, Pt foil-counter,
and Hg/HgO/KOH (1.0 mol dm−3) (MMO, 0.098
V vs. SHE)-reference.
20. Conclusion
• Carbon supported bimetalic PdIr catalysts by
reduction method using NaBH4 as reductant
and citrate as complexing agent.
• The onset potential of PdIr7/C is much more
negative than Pd/C
• Addition of Ir can remove adsorbed ethoxi
species.
21. M.C. Oliveira et al. / Journal of Power Sources 196 (2011) 6092–6098
Evaluation of the catalytic activity of
Pd–Ag alloys on ethanol oxidation and
oxygen reduction reactions in alkaline
medium
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
22. Letrature review
• Most polymer membrane reaseach efforts
were considering exclusively the acid
media.
• The reaction kinetics in alkaline media are
higher than that in acid media.
• Pd and Pd alloys have shown higher activity
for ORR an EOR for DAFCs specially in
alkaline media than traditional Pt alloys.
23. Objective
• In this work, Pd–Ag alloys
containing different amounts of Ag
were prepared and their intrinsic
catalytic activities towards EOR and
ORR in alkaline media
24. Experimental- Preparation of Pd–Ag
Preparation of Pd–Ag films (oxide film
intermetalic barrier), supstrates dipping
in SnCl2 & PdCl2 with de-ionized
water to seed stainless steel with
catalytc nucleous.
25. Experimental- Preparation of Pd–Ag
• Ag deposited at 60C and Pd at room temp.
• Both Pd &Ag deposisted in 10 ml plating
solution
• Rinsing (deionized water) & drying at 40C-
24h
• Annealing in argon atmosphere at 650C-6h
26. Exp. Pd-Ag films charchterization
• XRD
• SEM/EDS
• EOR study (scan rate 20mV/s in NAOH + ETOH 1.0
M)
• ORR study (scan rate 5mV/s in O2 staurated
NaOH solution 1.0 M
• Stainless steed coated with Pd-Ag film (0.169
cm2): used as electrode
27. Conclusion
• Pd-Ag alloys synthesised by electroless
deposition on stainless steel supstrate.
• Pd-Ag alloys: better activity for EOR than Pd the
highest active alloy is 21%Ag
• Pd-Ag alloys have better activity for ORR than Pd
at room temp.; the highest alloys is 8%Ag
• Future: preparation of Pd-Ag as nanomaterial
dispersed on carbon substrate.
28. international journal of hydrogen energy 36(2011)12686e12697
Pd-Ni electrocatalysts for efficient
ethanol oxidation reaction in
alkaline electrolyte
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
29. Literature review
• Production, storage, & transport of hydrogen for
PEMFC and Ethanol is alternative
• DEFC: ideal electrochemical device (without
carnot cycle limitations)
• Reported that PtSN catalysts than Pt-metal
• DEFC AEM & high effeciency (improved
kinetics, enhanced life time, reduced cost)
• Pd can break C-C in high pH media.
30. Objective
• Elegant organic sythesis solution for control
of nanoparticles thickness
• In this work, is saught to develop carbon
support Pd-Ni with different compositions
• Catalysts have 3nm distributions
• The correlation between enhanced EOR and
the Pd-Ni composition and structure.
31. Experimental
Pd/C, PdxNiy/C, and Pd1 Ni1 /CeNaBH4
catalysts preparation
Procedures of
nanocapsule
synthesis method
for preparing Pd1-
Ni1 /C catalyst
33. Tests
• cyclic voltammetry (CV)
• Linear scan voltammetry (LSV)
• chronoamperometry (CA)
• All potentials: vs. Hg/HgO (1.0 M NaOH)
electrode (0.140 V vs. NHE)
• First, (1.0mg catlyast+1.0ml ethanol) ultrasonically-
treated 5 min.
• Electrode: dropping 20 ml on GCE (covered .05%
TPQPOH solution
34. Conclusion
• A solution phase-based nanocapsule method:
PdxNiy/C catalysts, diameters (2.4-3.2nm), size
distributions (1-6nm) & surface areas (i.e. 68.0
m/g for Pd2Ni1/C)
• PdxNiy/C catalysts in alkaline medium: higher
activity towards EOR &’detoxification’ ability
• Ni could promote refreshing Pd active sites
• Nanocapsule method: efficient Pd&Ni contacts
35. Electrochimica Acta 75 (2012) 191–200
Co-deposition of Pt and ceria anode
catalyst in supercritical carbon dioxide
for direct methanol fuel cell applications
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
36. international journal of hydrogen energy 37(2012)9314-9323
Effect of decreasing platinum content
amount in Pt-Sn-Ni alloys support as
electrocatalyst for ethanol electrooxidation
Patrı´cia dos Santos Correa.a,*, Elen Leal da Silva.a, Renato Figueira da
Silva.b,Cla´udio Radtke.c, Berta Moreno.d, Eva Chinarro.d, Ce´lia de Fraga Malfatti
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
37. Letrature review
• Pt is the most favorable catalyst metal.
• Methanol is toxic.
• Ethanol is considered good alternative in low
temperature.
• Ethanol oxidation is complex and slow.
• Pt/C is most comum, but it is poisoned rapidly
(CO catalyst)
• The presence of Sn2O3 is favored and Si
causes dilatation of crystal lattic.
38. The work objective
• The use of impregnation/reduction method
• Ethyln glycol is the reducing agent.
• Using ctalayst alloys of PtNiSn/C
• Mesuring the effect of the composition on the
electrochemical behavior.
39. Experimental-Electrocatalysts preparation
1. PtSnNi/C Impregnation/Reduction
2. Ethylene glycol Reducing agent
3. Solution of H2 PtCl6.6H2O, SnCl 2.2H2O and NiCl2 (with 40%
metal) in ethylene glycol and water (75/25 v/v)
4. Adding carbon and agitation in ultrasonic bath dissolution of
salts.
5. Pure Pt, and Pt –Sn alloys were used to compare.
6. The PH is 12 and T is 130 C
7. Samples centrifugation and drying
8. Analyses of the results RBS, XRD, TEM
40. Experimental- Electrochemical characterization
• To determine the catalysts behavior in 1.0 M ethanol
and 0.5 M H2 SO4 solution (25 C, 10 min).
• Cyclic voltammetries CVs (PAR 273, scan rate of 50
mV/s+ 0.04 to 0.96 V potential range related to
saturated calomelan electrode (SCE)
• Electrochemical impedance spectroscopy
measurements were performed in potentiostatic mode
at 750 mV vs SCE (Solartorn SI 1255 coupled to a
potentiostat Omnimetra PG-05).
41. Results analysis
Diffractogram of
the Pt-Sn-Ni/C
(4 and 5) and
Pt/C-home made
electrocatalysts.
(*)Unknown
peaks.
42. Images obtained
from TEM (a)
PtSnNi/C - A and
(b) PtSnNi/C - B
and distribution
particle size (c)
and (d) of the
respective
electrocatalysts.
43. CVs obtained in a 0.5 M H2 SO4 and 1.0 M ethanol solution (scan rate of 50 mV/s)of
the: (a) PtSnNi/C - A, PtSnNi/C - B and Pt/C and (b) PtSn/C -C and PtSn/C - D
electrocatalysts.
44. Conclusion
• RBS results: impregnation/reduction process Pt-
Sn-Ni alloy particles with a composition control.
• XRD: Pt fcc structure
• The onset voltage for ethanol oxidation and the
current density with adding Sn & Ni to Pt.
• Decrease in Pt/Sn ratio: detrimental to catalytic
activity toward ethanol electrooxidation
• Adding Ni leads to decrease of charge transfer
resistence
45. Received: 17 February 2012 /Revised: 26 April 2012 /Accepted: 17 May 2012 # Springer-Verlag
2012
Preparation of PtSnRh/C-Sb2O5·SnO2
electrocatalysts by an alcohol reduction
process for direct ethanol fuel cell
J. C. Castro & R. M. Antoniassi & R. R. Dias & M. Linardi
& E. V. Spinacé & A. Oliveira Neto
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
46. Literature review
• The attention for new DEFC catalysts
• (Pt + Co catalyst) is the most comum.
• PtSN is a very good but acetaldhyde& acidic
acid are produced.
• Adding Rh to PtSn DEFC Co2
• Another: to deposit Pt,Sn,&Rh nanoparticles
on metal oxides CeO2,RuO2, SnO2
• Pt nanoparticles supported on C &/or ATO
47. Objective
• To prepare PtSnRh/C-Sb2O5·SnO2 with
different atomic ratios
• Using the alcohol reduction process to study
the catalysts effect on ethanol electrooxidation
• Comparing the results of PtSnRh/C-
Sb2O5·SnO2 with those of PtSnRh/C (the
reported most active ternary catalyst.
48. Experimental
• Electrocatalysts PtSnRh/C-Sb2O5·SnO2 : prpared
from H2PtCl6·6H2O, SnCl2·2H2O, & RhCl3·xH2O
as metal sources in one step,
• Pt/Sn/Rh (90:05:05, 70:25:05, & 50:45:05)
• Ethylene glycol as solvent and reducing agent,
• physical mixture of Vulcan XC72 (85 wt%) and
Sb2O5·SnO2 (15 wt%) as supports.
• XRD for PtSnRh/C & PtSnRh/C-Sb2O5·SnO2.
• TEM, CV & CA were also carried out.
49. Experimental
• DEFC tests: anode PtSnRh/C-Sb2O5·SnO2 &
cathode Pt/C in single cell (A= 5 cm2)
• DEFC; carbon closth as GDL & Nafion® 117
membrane as electrolyte
• Electrodes: hot pressed on both sides of
membrane at 100C, 2 min, 225GPa
• Pt/cm2 of electrode is 1 mg, T(O2 humidifier)= 80
°C, O2 flow 500 mL/min, & 2 bar
50. Conclusion
• Alcohol reduction: producing in a single step of
PtSnRh/C-Sb2O5·SnO2 for ethanol oxidation.
• Structure fcc for Pt & Pt alloys.
• Nanoparticle size distribution 2-3 nm.
• PtSnRh/C-Sb2O5·SnO2 (90:05:05) & PtSnRh/C-
Sb2O5·SnO2 (70:25:05): exhibited higher
performance than PtSnRh/C.
51. international journal of hydrogen energy36(2011)849-856
Electrolless Ni-B supported on carbon
for direct alcohol fuel cell
applications.
H.B. Hassan, Z. Abdel Hamid
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
52. Letrature review
• In this paper, the previous research efforts
about Ni-B coatings for different uses. One of
them is the electroless. Refs [1-10]
• The srtucture of Ni-B coatings depends on the B
content; <0.8 NANOcrystalline and >=20%
AMOrphous.
• The AMOrphous alloys have excellent catalytic
properities, so they are used in hydrotreating
operation.
53. The work objective
This work aims to investigate the
catalytic activitiy of Ni-B coatings
supported on comercial electrodes
using electroless technique and have
come from acidic path towards the
electrooxidation of some alcohols
(ethanol and methanol.
54. The experimental preparartion
• The Dimethyle Amine Borone (DMAB)
was used as a reduceing agent.
• The acidic plating path was 5 g/l
Nicl2.6H2O, 7 g/l NaC 2 H 3 O 2 2 O, 7
g NaC 2 H 3 O 2 , 1.0 g/l (DMAB)
• Operation conditions are PH 4, &T 60C.
55. Electrode preparation
1. Mechanical polishing
2. Degreased with acitone
3. Rinsed with distilled water, and
4. Dried with soft paper
Three different NieB/C samples (I, II and III)
were prepared at different deposition time of
30, 60 and 120 min, respectively.
56. Electrical measurements preparation
• The electrochemical measurements were
performed using an Amel 5000 system
(supplied by Amel instrument, Italy) driven by a
PC for data processing.
• The phase structure of the coatings was studied
using XRD and The surface morphology was
observed using SEM.
• the boron content was determined using
inductively coupled plasma-mass spectrometer
(ICP-MS)
57. Results and Discussion
• The Ni-B coating deposites decrease with the
deposition time.
• The coatings are uniform and they consist of
agglomerates of nickel that are randomly
distributed, these agglomerates slightly
increase as the deposition time increases.
• the material is microcrystalline nickel that
considered as amorphous
58. Received: 12 January 2012 / Accepted: 10 May 2012v Springer Science + Business Media B.V.
2012
Platinum nanocatalysts prepared with different
surfactants for C1–C3 alcohol oxidations and
their surface morphologies by AFM
Salih Ertan,Fatih S¸em,Selda S¸em,Gu¨lsu¨n Go¨kag˘ac
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
59. Lterature review
• Metal nanoparticles (MNPs): used in catalytic
reactions due to larger surface area than bulk
• Surfactants: to prepare surfactant-stabilized
PtNPs
• MNPs: oxidation of alcohol to CO2 (DAFC)
• DMFC & DEFC are the comum examples
• Methanol: toxic & Ethanol: CO catalyst req.
• Longer chain alcohols (2-propanol): energy
density
60. Objective
• Pt : the most active electrocatalyst
• To produce PtNPs using PtCl4(starting)+ surfcants
(1-octanethiol,1-decanethiol,1-dodecanethiol, &1-
hexadecanethiol)
• These catalysts: to determine surfactants chain
length on alcohol oxidation.
• XRD, XPS, AFM, CV, & CA were carried out on
the catalyst samples.
61. Experimental
• Catalyst is prepared by staring material PtCl4.
• Catalysts I,II,III, and IV were prepared by
super hydreide/reduction method (Ki-Sub et al. 2004; Sen et
al. 2011)
62. Ctalayst preparation
• PtCl4 (99 %) was obtained from Alfa, tetrahydrofuran (THF) (99.5
%)
• Methanol (C99.5 %), ethanol (99.9 %), 2-propanol (C99.5 %) and
HClO4 (60 %) were purchased from Merck.
• Lithium triethylborohydride (superhydride) (1.0 M dissolved in
THF)
• 1-octanethiol, 1-decanethiol, 1-dodecanethiol and1-hexadecanethiol,
were bought from Sigma-Aldrich,
• Carbon XC-72 was acquired from Cabot Europa Ltd.
• All chemical reagents in this study were of analytical grade purity.
63. superhydride/reduction method
• 0.25 mmol (0.0808 g) of PtCl4 was completely dissolved in
small amount of anhydrous THF
• 0.25 mmol of surfactants was added to this solution.
• Finally, superhydride and ethanol were added to reduce
the thiol-stabilized platinum complex up to the
observation of a brown color in the solution
• dry ethanol was used to wash the resulting solution
• the solution was centrifuged for an hour
• Finally, the solid Pt nanoparticles were dried under
vacuum at room temperature.
64. Structural & morphological analyses
• TEM: to determine the size of platinum
nanoparticles.
• Samples: prepared by sonicated (10 min) CCl4
suspension
• Suspension drops: deposited onto carbon
covered 400-mesh copper grid & the solvent
allowed evaporating before analysis.
• XPS: to deduce Pt oxidation states
• XRD, CV and CA measurements were carried out.
• SCE: reference, glassy carbon: counter, catalysts:
electrodes
65. Electrode preparation
• C powder (36.78mg) + nafion(0.5mL)+N,N-
dimethylformamide(0.15mL)+distilled water
2.5 mL homogeneous solid solution.
• the solution: dropped on 7 mm (dia) of glassy
carbon electrode.
• The electrode: dried at 40, 65C for 20min
• The electrode: heated to 100C for 1h adhesion
66. Further analyses
• ICP to determine the Pt amount.
• AFM to specify the surface topography.
• All measurements:0.01–0.025ohm-cm
antimony-doped silicon probes (2 nm R,328–
379 kHz RFs) spring(K)= 20–80 N/m
• prepared catalysts: suspended in a deionized
water
• Solvent evaporated at room temperature
67. Results & Discussion
XRD of blank
(a), catalyst I
(c), II (d), III
(e), and IV (b)
68. High resolution
transition electron
micrograph and
particle size histogram
of catalyst I.
Transmission electron
micrograph of catalyst
III
69. a. AFM images of catalysts. b Histogram of height of particles obtained from AFM data. c
Histogram of lateral diameter of particles obtained from AFM data
70. Journal of Power Sources 195 (2010) 1001–1006
7/26/2012
Synthesis of PdNi catalysts for the
oxidation of ethanol in alkaline direct
ethanol fuel cells
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
70
71. Objective
7/26/2012
Is to quantify the quality of PdNi/C
catalyst for alkaline DEFC using NaBH4
as reductant, and to use Pd/C for
comparison purposes through the
XRD, TEM, XPS, ICP-AES tests.
71
72. Experimental Catalyst Synthesis
7/26/2012
• The cehemicals are PdCl2, NiCl2 ·6H2O,
KOH, NaBH4, HCl, CH3CH2OH & Vulcan
XC-72 carbon (particle size 20–40 nm)+ 5
wt.%(PTFE) emulsion
• PdCl2, NiCl2 ·6H2O dissolve in DI water.
• C powders: suspended in the resulting
• 2 wt.% NaBH4 added
72
75. Conclusion
7/26/2012
• FCC phase of Pd is present and Ni(OH)2 on the
C powder
• TEM &EDS images show the well-dispersed
metal particles on the C powder & well
distribution
• CV, CP: Pd2Ni3/C superior activity to EOR
• Ni oxidized state distributed over Pd, proved
to be enhancing EOR.
75
76. Journal of Power Sources 218 (2012) 148 - 156
7/26/2012
Ni nanowire supported 3D flower-like Pd
nanostructures as an efficient
electrocatalyst for electrooxidation of
ethanol in alkaline media
By:
A.M.Sheikh
LAPEC (Corrosion Research Laboratory) – UFRGS
Ahmad.elsheikh@hotmail.com
76
78. Objective
7/26/2012
Synthesizing novel hybrid (Ni nano wire array)
NiNWA/PdNF(nanoflowers) electrocatalyst
using one-dimensional (1D) and conductive
metal NiNWA as a support for the PdNF by
electrodeposition of NiNWA using
polycarbonate template and the reduction of Pd
as NF onto the surface of NiNWA through
borohydride hydrothermal reduction method.
78
79. Experimental- Synthesis of NiNWA
7/26/2012
• Polycarbonate template was coated by a 400 nm
thick layer of Ni using thermal evaporation
technique
• A Cu wire was connected to the Ni backside of
the template by Ag paste
• Solution: Nix(So4)y+ NixBry + H2Bo3 + ANKOR
• A 2 electrodes cell: anode; Ni pellets in a Ti-
basket, cathode; Ni/porous polycarbonate
template 79
80. Synthesis of NiNWA supported PdNF
7/26/2012
• NiNWA preparation (0.5 *0.5 cm2) 1 M nitric
acid for 1 min washed in DI water
• PdNF preparation (NaBH4 hydrothermal
reduction with salt (10 mM PdCl2) in water)
• NiNWA piece immersed in 5 ml glass tube ,
0.5 ml aliquots of Pd metal precursor salt at
80C
• NiNWA/PdNF electrocatalyst: removed &
washed in Di water 80
83. 7/26/2012
BF TEM images of transverse cross-section showing (a) PdNF at the surface of a Ni nanowire, (b)
high magnification region of (a), and (c) a full coverage of Pd that varies in thickness from w50 to
100 nm. (d) A diffraction pattern confirming the presence of Ni and Pd, and the lattice parameter of
83
84. ) Cyclic voltammograms of NiNWA/PdNF
in 0.5 M KOH solution, and in 0.5 M KOH þ
7/26/2012
1 M EtOH solution in the hydrogen
adsorption/desorption region (scan rate:
50 mV s 1 ). Inset shows the magnified
view of onset potential region of cyclic
voltammograms.
(a) Cyclic voltammograms of
NiNWA/PdNP and NiNWA/PdNF for
the electrooxidation of ethanol in
0.5 M KOH þ 1 M EtOH solution.
Conditioning/initial potential: 0.55
V, 20 s; scan rate: 20 mV/s
84
85. 7/26/2012
(a) Cyclic voltammograms of NiNWA/PdNF for the electrooxidation of
ethanol at different scan rates in 0.5 M KOH þ 1 M EtOH solution, (b)
Plot of forward anodic peak current density and the corresponding
peak potential at different scan rates.
85
86. Conclusion
7/26/2012
• Ni nanowire array supported three dimensional flower-
like Pd nano-electrocatalyst and investigated their
electrocatalytic performance toward electrooxidation
reaction in alkaline media
• 1D metallic Ni nanowire array can be used as a noble
metal catalyst supports as an alternative to CNTs
• Ni nanowire array/Pd nanoflowers electrocatalyst
exhibits large electrochemically active surface area ,
higher stability and poisoning tolerance than Pd
nanoparticles
• Inherent nature of the abundant grain boundaries and the
three-dimensional open nanostructure of the Pd
nanoflowers.
86
